1. Field of the Invention
This invention relates to an insulation blanket that is provided at an aircraft fuselage that is equipped with a sealing device between a through element and said insulation blanket as well as an aircraft that is equipped with said blanket.
2. Description of the Related Art
FIGS. 1 and 2 diagrammatically show a transverse cross-section of an aircraft fuselage 10.
The aircraft fuselage comprises a skin 12 with an outside surface 14 that is in contact with the outside environment of the aircraft and an inside surface 16 and a passenger cabin 17.
In a flight phase, an air-conditioning system makes it possible to keep the temperature inside the cabin 17 around 20° C. with a constant relative humidity for the comfort of the passengers whereas the temperature outside of the aircraft is around −50° C.
To limit the losses and to ensure comfort to passengers, at least one insulation blanket 18 is provided at the inside surface 16 of the skin of the fuselage.
After the installation of this insulation blanket 18, there is a space between said blanket 18 and the skin 12 at the level of which the hot and moist air coming from the cabin 17 circulates.
During flight, the inside surface 16 of the skin has a temperature that is less than 0° C. although the humidity that comes from the cabin tends to condense and to freeze at said surface 16.
During the landing phase, the temperature of the air outside of the aircraft is increasingly warm although the ice that is formed at the inside surface 16 tends to melt and to drip onto the insulation blanket 18 up to the lower part of the fuselage where the condensates are recovered and then removed.
Consequently, in addition to its function as insulation, the insulation blanket 18 serves to seal the inside of the aircraft and to drain the condensates to prevent them from dripping on the passengers or on sensitive systems, such as, for example, electrical circuits.
To ensure these two additional functions, the insulation blanket 18 comprises an impermeable film at its surface opposite the inside surface 16 of the skin of the fuselage.
According to one embodiment, an insulation blanket consists of a layer of a thermally insulating material, such as, for example, glass wool, bagged in an airtight plastic film.
Generally, this insulation blanket 18 is made of several parts that are juxtaposed in such a way as to cover the inside surface 16 of the skin of the fuselage. As illustrated in FIG. 2, at a junction zone, the parts overlap and are arranged like tiles. Adhesive strips can also be used to join the two parts and thus to improve the seal.
The seal of the insulation blanket 18 may prove problematic at the passage of a through element 20 connected to the skin 12, such as, for example, a support in yoke form that ensures the attachment of a connecting rod 22 or link as illustrated in FIG. 3.
Hereinafter, an element that is connected to the skin, that passes through the insulation blanket and that offers, for example, an attachment system for maintaining systems or components of the aircraft, is called a through element.
According to one method for installing the insulation blanket 18, at the level of a through element 20, the blanket 18 is cut to allow it to pass. This installation method is not satisfactory because with the blanket 18 not having any mechanical strength, the edge of the cutout is not kept flattened against the through element 20 although there is always play between this element 20 and the blanket 18 that no longer makes it possible to ensure an optimum seal.
To reinforce the mechanical strength of the blanket 18, it is possible to add a foam block with closed cells, bonded to the blanket 18 and comprising a slot for allowing the through element to pass.
This foam block is light and easy to make integral with the blanket 18 and in a first step makes it possible to ensure a satisfactory sealing barrier.
However, the foam block does not have an elastic property or gradually loses it although play appears between the foam block and the through element that no longer makes it possible to ensure an optimum seal.